


custom-fit to his heart's desire

by suitablyskippy



Category: Durarara!!
Genre: F/M, Obsession, Stalking, Thoroughly Toxic Romance, Unhealthy Relationships
Language: English
Status: Completed
Published: 2015-04-19
Updated: 2015-04-19
Packaged: 2018-03-24 21:13:54
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,458
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3784489
Author URL: https://archiveofourown.org/users/suitablyskippy/pseuds/suitablyskippy
Summary: <blockquote class="userstuff">
              <p>“Maybe I’ll kill you myself,” Seiji says. His voice is apathetic.</p><p>“The last time you tried to kill me was the best thing that’s ever happened to me,” says Mika, and gives his hand a reassuring squeeze. She can afford to be reassuring. He’s never going to find that woman's head.</p><p>(Mika worked hard to earn her happy ending. It's time to make the most of it.)</p>
            </blockquote>





	custom-fit to his heart's desire

**Author's Note:**

> [I've watched the first series of the anime, and read the first light novel; apologies if this contradicts anything from later/other parts of canon!]

The apartment door slams behind them that first night. Seiji seizes her by the collar of her shirt and yanks her in, her body pressed close against his own, and she clutches at his shirt and presses closer. 

“Seiji-san,” says Mika, “oh, _Seiji_ -san—!” and she curls her own hand over his, where it’s fisted so tightly in her collar that stitches are popping. She gazes up at him, her voice breathy with wonder. “Seiji-san, I love you, I’m yours, I love you –”

His hand hits her chest. Her back hits the wall. Mika shrugged her old self off like a cardigan on a hot day – unnecessary, stifling – and even though she knows much better than to believe Seiji would ever hurt her now, trace memories of that old self remain: and for a giddy, foolish instant, Mika’s expecting the concussive impact of her skull against concrete. 

It never comes, of course. Her head smacks back against Seiji’s hand, there to protect her. 

“Once I get the real thing back, you’ll be gone.” His voice is low, dulled into flatness. His fingers splay through her hair and a thrill jolts out beneath her skin. “As soon as my love comes back to me. Gone.”

“But until then,” says Mika. She flattens her hand against his chest, light-headed with love; she gazes up into his face until she’s nearly lost in him, dizzy all over again with how it feels to be _Seiji’s_. “Let me be her, Seiji-san – just the way we were, just until you have her, I can be her, I promise you –”

Seiji stares down into her eyes like something is stagnant behind his own, dead and dark. “I hate you,” he says. 

Mika doesn’t hesitate at all. “You love me,” she says. “You love Celty – I _am_ Celty. Your Celty, Seiji-san! I’ll be your Celty _forever_ –”

“I hate you,” says Seiji. His voice is blank. It doesn’t matter. None of it matters. Mika wraps her arms around his shoulders and presses her mouth against his, and lets him kiss her the way he’d never dared to kiss her even once, when she was Celty. His breath is hot; his grip digs into her waist so hard that once her skirt drops to the floor there are marks left where his fingers had been. 

A trail of clothes falls behind them from the hallway to the bedroom, starting with her shirt and followed by his, a flurry of skirt and pants and underwear and kicked-back sheets; the last thing to go is Mika’s hat, which Seiji removes himself, reverently careful, smoothing down her hair where it’s rumpled against the pillow beneath it. 

“I –” _love you_ , she doesn’t say, because abruptly Seiji covers her mouth. 

“It’ll be okay, Celty,” he says, and looks at her. There’s something funny in his eyes. A moment later, he lifts his hand away. 

Mika’s got the message. She was Celty for weeks. She can be Celty again. She whispers his name and gazes up at him, anxious – not _too_ anxious – trusting – not _too_ trusting. She touches her fingertips to his bare arm, shy and feather-light. 

Seiji’s staring down at her, his hands flat against the pillow either side of her head. The only light in the room is coming from the street outside, a desaturated wash of neon that flattens his stare to blank reflection. “Look at me,” he says, at last. “I want to see her eyes.”

Mika nearly speaks. She stops. She nods. 

“Okay,” says Seiji. “Okay,” he says again. He kisses her. It’s not romantic, but Mika never wanted romance. She wanted Seiji. She has him. She kisses back. 

 

+++

 

He calls her Celty and tells her he loves her, and Mika doesn’t say anything that might sound like she’s suggesting Celty doesn’t deserve his love – but really, what _has_ she done? She had a pretty face, and then she lost it. Careless! Mika had a pretty face too, before she lost it, but at least _her_ pretty face was lost to a better cause – a calculated, strategic cause. The Headless Rider was nothing more than plain old careless. __  
  
She wakes up in the night to find Seiji watching her. He’s lying on his side, very still; his eyes are open and blank, illuminated by the digital red light of his bedside clock. Mika watches him back for a little while. This has happened before. She’ll say his name, and thenthe warmth will come back into his eyes and very gently he will pass his knuckles along the line of her cheekbone. _Don’t worry, Celty_ , he’ll say, and then he’ll say: _I love you, Celty_ , _I’ve always loved you, I will always, always –_

Mika whispers, “Seiji-san?” 

Seiji says nothing. His stare is empty. For a moment, she wonders if perhaps he’s fallen asleep with his eyes open – but then his gaze tracks down, just slightly, to her throat. 

“I love you,” says Mika. She finds his hand under the sheets and holds it tightly. “I love you so much, Seiji-san. _So_ much.”

He says nothing. He’s still watching her when she slips back into sleep, his fingers limp and unresponsive and linked in hers. 

 

+++

 

The alarm goes off at six-thirty. Seiji rolls blearily over to turn it off, and when he rolls back Mika kisses him good morning. He doesn’t try to stop her, so she kisses him again, and again, until finally he lets out a grunt of irritation and pushes her off. He goes into the bathroom. The door closes. The hiss of water begins. 

Mika slips her tablet out of her schoolbag. She brings up the feed from the four CCTV cameras she installed with the clearest view of Seiji’s bed, and tucks herself up against the headboard to watch the silent, black-and-white movement of their bodies. As grainy as the footage is, and as silent and ill-lit, it looks like a fight more than anything else: strange and soundless, like something underwater. She watches, her hand at her throat, tracing absently along the line of puckered skin. 

Mika’s hand is still at her throat when Seiji leaves the bathroom in a cloud of steam. She watches him go through his wardrobe, watches him pick out his uniform, watches him dress. “Do you think we’ll get married?” she asks, while he’s buttoning his shirt. He snorts in what might be disgust. “Our children –”

“– would be yours,” says Seiji. “Not hers. So no.”

He sits to pull his socks on. Mika watches him, watches the way his back shifts beneath his shirt. She says, “Your sister’s a scientist.”

“My sister’s none of your business.”

“There must be a way,” says Mika, hardly listening. “If she has samples from the head, there must be a way... to extract its genes, or something. I don’t know. To take it inside me. There must be a way.”

“Are you gonna take a shower or what?” says Seiji. 

From now on, all of Mika’s mornings will be like this. Today, and tomorrow, and the day after, and each day will be followed by another, forever and ever, for the rest of her life – for _eternity_. The thought is like sunshine flooding through her, warming and golden. Mika slips her tablet back inside her schoolbag and passes by Seiji’s desk on her way to the bathroom; she wraps her arms around him from behind, presses a kiss against his cheek. 

“I love you,” she says. 

Abruptly Seiji turns in his chair. He seizes her by the arm and stares, for a moment – searching her face, close and intent. 

“I –” He stops. Mika barely dares to breathe. He stands, and she doesn’t step back: they’re close, _so_ close. His palm touches her hair. He brushes it back from her face. “I love you,” says Seiji, monotonous. “I love you,” he says, again. “I love you. I love you so much. I’ll love you forever.”

“Oh, _Seiji_ -san –!” 

The soothing motion of his hand against her hair goes still. “Not you,” says Seiji. “Her.”

Mika doesn’t care. She doesn’t care in the slightest. Seiji gives Mika his love as a proxy for Celty, but the only part of that that matters is the part where Seiji gives Mika his love. 

 

+++

 

On the walk to school, they hold hands. There’s an overpass where four days ago Seiji had stopped and turned to her, and put his palm against her cheek, and the city had grumbled into life beneath them as they gazed, transfixed, into each other’s eyes. They cross it now, and Mika tugs on his hand. Seiji stops. They stand at the rail, looking out over the city. The neon skyline is blinking awake, though its lights are dim in the morning sunshine. There’s a constant rattle of exhaust as traffic rushes under them. 

Seiji’s hands curl around the rail. Mika presses closer, and tucks her arm through his so she can rest her fingers at his wrist: small, pale, careful. His school blazer is bluer than the sky itself. Perhaps Seiji would like it if she wore hers as well. She asks him. 

“I don’t care,” says Seiji. “Dress like Celty would.”

Mika pats her fingers against his wrist, playful. “Seiji-san, I’m already Celty!” 

Seiji says nothing. He’s looking at her hand on his wrist, but Mika’s mind is already racing onwards. What she’s wearing now – the pink, the pleated skirt, the cat-eared beanie – it says ‘cute’, and ‘lively’ and maybe ‘carefree’, and she wore it to break into Seiji’s apartment on the last day of her past life because after an entire summer’s worth of rigorously devoted stalking, Mika had _still_ picked up no clues about what he might like in girls: and in her extensive prior experience, ‘cute’ tended to be a safe bet. Of course, she knows now that what Seiji likes best is just a disembodied head, and Mika still can’t offer him that – but she can undo the top buttons of her blouse so that the scarring at her neck is all the more visible, and she can tip her head, pliant and docile as a doll, and she can act as though she’s seen the world only through several litres of stagnant preservative for the last few decades... She can be what he wants. She _is_ what he wants. 

“I hope you die,” Seiji says at last. “Not yet. Once Celty’s mine. Then no one will need you, and I hope you die.”

“I –” _am your Celty_ , Mika begins to say, but Seiji picks her hand from his sleeve as though it’s something he dropped and never meant to land there, and quickly she twines her fingers between his. They start walking. 

The roar of the traffic is growing louder. Sunlight dazzles from glass and buildings stare ahead, their windows blankly, blindingly bright. The morning mist is dissipating; in its place, exhaust fumes are rising. 

“Maybe I’ll kill you myself,” Seiji says. His voice is apathetic. 

“The last time you tried to kill me was the best thing that’s ever happened to me,” says Mika, and gives his hand a reassuring squeeze. She can afford to be reassuring. He’s never going to find the head. 

 

+++

 

Seiji’s homeroom teacher is confused to see him back and more confused still to see Mika, returned apparently from the dead and wholly unrecognisable. None of the teacher’s questions are ones Mika wants to answer, so she wilts when he asks them; she clutches Seiji’s arm and presses close to him; she ducks her head and whispers monosyllables, meek and submissive. Harima Mika has always taken a creatively-minded approach to problems, but Seiji’s Celty would never do the same: together they’re a perfect match, and Mika can pretend to be just as helpless as Seiji needs her to be. 

The instant the staffroom door shuts behind them, Seiji backs her against the wall. “My love,” he says, “my soulmate, Celty, you’re perfect, I –” he breaks off, to kiss her nearly giddy, “– love you, I _love_ you –”

Mika remains obligingly mute, obligingly pliable. Seiji likes it when she’s helpless. If it helps him forget that she’s not Celty, Mika will pretend for him just as often as he wants. 

 

+++

 

Lessons pass in a haze of lovestruck daydreams, which is much the same way that all lessons have passed for Mika since middle school. Over the years, her daydreams have co-starred a wide variety of boys: all of whose extensive and rigorously gathered information dossiers she threw into an industrial furnace the very day she first met Seiji, because Mika had recognised instantly that what she and Seiji shared was special, and would grow into a love far greater than any she had ever known before, and would require a stalking campaign _unprecedented_ in scale before she could even _begin_ to comprehend the depths of Seiji’s perfect, exquisite, romantic soul. 

Mika’s stalking has always been disapproved of by the city’s police, unable to see past the home invasions to the pounding, lovestruck heart that drives her. The police would probably disapprove of Seiji having tried to murder her, too, unable to see past the bloody violence to the lovestruck heart that had driven _him_. And if Mika were to boil Celty’s head down to the bone and serve the broth up for her evening meal – well, she imagines the police would probably disapprove of that, too, for over the years Mika has come to accept the unfortunate fact that Tokyo’s police force understands nothing whatsoever of what it means to be in love. 

The mathematics of their love really is quite simple, though of course Mika has always excelled at both mathematics and at love: Seiji loves the head. The head is Celty, and Mika is Celty too, so it follows only naturally that Seiji loves Mika. And from that, it follows more naturally still that Mika must destroy the head so that Seiji will love Mika alone, and just as naturally – though perhaps less obviously, to anyone less comprehensively versed in the art of love than Mika – it follows that the only way Seiji could ever love Mika more would be if she and the head became one. Thus: Seiji’s two loves, united forever in Mika’s digestive tract! 

Mika thinks of it, dreams of it fondly, imagines how bright the flame of his passion would burn – brighter than before! brighter than _anything_ before! love of a brightness unknown to history! – and she sits through her lessons with her cheek in her hand, and the collar of her shirt pulled aside, just so. 

At the next desk is Seiji; she can see him from the corner of her eye, and again and again his gaze finds her throat, tracking back to it as though he just can’t help himself. His broad hands are flat and still against his desk. Whenever Mika catches him looking, his stare is focused, dark with hunger and preoccupied by the scarred ring at her throat; more than once, she sees him wet his lips. 

 

+++

 

Mika wasn’t reborn after the surgery. From the heavy, muffling weight of anaesthetic, she emerged as something far, far better than reborn: she was _remade_. Precisely custom-fit to the exact specifications of Seiji’s heart’s desire. Topiary of the self, trimmed into a shape that could be loved. Blearily, she had stared upwards. 

Upside down, craning over her, the outline of the doctor was limned dazzlingly bright by the surgical lights. “Back with us?” he asked, while three fuzzy copies of him swam side to side across her vision. “Blink if you can hear me. Or if you need to lubricate your eyeballs, I suppose, but since things are going to be a bit painful in that area for a few days I’d say that my professional medical advice on the subject would be to refrain, in general terms, from going too far with the blinking. Blink merely as and when you need to. No more, no less. Are you with me?”

Mika supposed she was. She blinked. 

“Good,” said the doctor, and leaned in. Another half a dozen copies of him swayed into blurred existence with the motion, before resolving into one. “When you’re asked, you say that you’re Celty.” He hadn’t paused to let her repeat it back, and it was just as well: Mika’s mouth was dry and unfamiliar. “Though I shouldn’t imagine you’ll have to make a conscious effort to remember the name for long, the world of cognitive reprogramming owes a _lot_ to Yagiri Pharma, I don’t think it’s unreasonable on my part to assume you’ll end up with your brain refitted too, soon enough –”

“Sensei,” said someone, in a tone of icy warning, and he swerved easily back to the subject of Celty – of Celty, who Seiji once had owned – of Celty, who Seiji loved with all his heart – of Celty, who Mika has become. 

The head had been his property; he had owned it and he had loved it, and now the head is gone, and in its place is Mika. All around her throat, the proof is there: collared by her love for him, devotion scarred into her skin. 

 

+++

 

Hand in hand they walk home together, through the busy, exhaust-fume haze of an Ikebukuro afternoon. The insistent blast of car horns, the frantic press of the crowds, the tinny, chaotic discord of music blaring from the open storefronts of a hundred shops, a thousand shops, a hundred thousand dazzlingly neon-lit shops... Mika cries out in delight and hurries to the plate-glass window of one of them, and Seiji allows himself to be towed along with her, allows her to point out the cat-eared hoodie on display, allows her to hurry him inside so he can see her try it on. 

Mika leaves him standing listlessly outside the changing cubicle, and he’s still listlessly standing there when she opens the curtain again: looking at the far wall, no light in his eyes. 

She touches his arm. “Seiji-san? Do you like it?” 

“I don’t care,” says Seiji. She reaches up to cup his cheek. He lets her. Gently, she tips his face down so that his eyes meet hers: blank, empty, hollow of anything but darkness. Her heart swells so sweetly full of love she can hardly bear it; she clasps his hands between her own, gazing up at him, searching his face to track down every last part of his perfection. “About any of it,” Seiji continues, flat and dull. “I don’t care about anything any more. I don’t care about you.”

“Oh, _Seiji_ -san,” says Mika, breathing out his name on a rapturous sigh. Love is pounding in her heart; over its frenetic rhythms, she can hardly hear him. 

“You ruined my life,” says Seiji. His voice is monotonous. “I used to care about things. I remember that. I remember caring. You’ve destroyed me.”

“I’ll get the hoodie,” Mika decides, and the rest of the walk home is brighter still, so bright it’s all she can do not to skip. Seiji on one arm, her bag swinging from the other: never was there ever a luckier girl in the world than Harima Mika! Never was there ever a girl who deserved her happiness as much as Harima Mika! Never was there ever a girl who worked so hard, who sacrificed so much, who endured such terrible, beautiful, exquisite trouble for her love as Harima Mika, and never will there ever be again! 

They go up the stairs to their apartment, and as Seiji reaches for his keys her love overtakes her, once again: she pushes up and kisses him, and he lets himself be kissed, again and again, until he lets himself forgets that she’s not Celty – and then he kisses back. 

Minutes, hours, days, weeks: time is irrelevant, for those who are young and in love, and when at last Seiji shoves her away from him it could be the next century, for all Mika cares; the world could have ended around them, Ikebukuro could be ashes. She has Seiji; she needs nothing else. 

He wipes his forearm across his mouth with a grimace of disgust as he unlocks the apartment door. Seiji hasn’t given Mika a key of her own, but that doesn’t matter: Seiji has a key, and Mika will be at his side forever. Mika could have opened the door more quickly with her lockpicking gun, once upon a time – but that lockpicking gun belonged to a version of Mika who Seiji didn’t love, and she threw it out long ago. It’s important to make compromises in a relationship, after all. A lockpicking gun is only the least of what Mika has given up to shake off the chrysalis of that unloved self.

 

 

 

**Author's Note:**

> [I feel like Mika and Seiji are what happens when several different brands of nightmare fuel get poured into the same container and shaken up together, then set on fire, then thrown off a cliff; I still can't believe canon gave me such a perfect, horrifying ship, I love them so much. Any comments would be appreciated! ♥]


End file.
